title: Intense isolated attosecond pulse generation in pre-excited medium.
abstract: We present a theoretical study of isolated attosecond pulse generation in pre-excited medium driven by an intense few-cycle laser pulse. We show that the generation of the macroscopic xuv supercontinuum is governed by the initial population of the excited state. Large initial population of the excited state leads to the high density of the free electrons in the media and strongly changes macroscopic properties of the driving pulse and the supercontinuum, and diminishes the isolated attosecond pulse generation. Instead, small initial population of 5% in the pre-excited media subjected to the few-cycle driving pulse can produce well phase-matched xuv supercontinuum, and a pure intense isolated attosecond pulse with the pulse duration of approximately 150 as and the pulse energy up to 0.5 nJ is directly obtained.
authors.affiliation: Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Weiyi
authors.initials: W
authors.lastname: Hong
authors.forename: Qingbin
authors.initials: Q
authors.lastname: Zhang
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Zhu
authors.forename: Peixiang
authors.initials: P
authors.lastname: Lu
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D008027:Light; D008029:Lighting; D008962:Models, Theoretical; D012542:Scattering, Radiation